RunTimeException Error in process of test generation

[JaneEugenia]

Description

While choosing several classes randomly for test generation, if at least one Interface has been chosen along with classes, tests are not generated at all. Besides, sometimes two RunTimeException errors appear while trying to generate tests.

To Reproduce

Steps to reproduce the behavior:

Example:

1. Run IDEA Commit cab4799
2. Use org.utbot.examples.mock to generate tests
3. Choose a couple classes and at least one Interface
4. Check the result

Expected behavior

Tests are supposed to be generated for classes anyway, ignoring chosen interface.

Actual behavior

If at least one Interface has been chosen along with classes, tests are not generated neither for Interface nor for classes, both are ignored.
If we choose classes only, everything goes fine, tests are generated.

Visual proofs (screenshots, logs, images)

Environment

IDEA Commit cab4799
Test framework: JUnit4
Mock strategy: other packages: Mockito
Mock static: No static mocking
Timeout: 60 sec